Phasing device for synchronous telegraph systems



y 1 J. L. cALLAHAN PHA SING DEVICE FOR SYNCHRONOUS TELEGRAPH SYSTEMS Filed Jan. 1, 1945 MHG/VET/G raps nvsuz. a rave 0.9044

.INVENTOR aZZaYuzn A'i'To RNEY Patented July 4, 1944 7 2352.688 rnssmc nnvrca FOR svncnnonous TELEGRAPH SYSTEMS John L. Callahan, Malverne, N. Y., asslgnor to Radio Corporation of America, a corporation of Delaware Application January 1,1943, Serial No. 471,030

14 Claims. (Cl. I78-53) This invention relatesto a phasing device for synchronous telegraph systems. When code signals having uniform length are employed insynchrohous printing telegraph systems, it is frequently desirable to extend the transmission channel from one receiving station to another. It is also desirable in multiplex'systems to adjust the'phase of the multiplex signals originating at different points in the system so that they will not overlap the channels to which they are as-' signed. A distributor may be provided with individual segments for the code elements and may, for example, contain a sumcient number of suitable arrangements are provided for delaying the effects of the received signals so that the several components of a character code signal may be impressed on appropriate segments of a transmitting distributor in proper phase relation to other operating parts of the system.

Heretofore it has been the practice in the tele graph art to utilize storage means of one type or another such as banks of relays, for example, for. delaying the transmission of relayed code signals so as to tie in properly with the channel time which is allotted to agiven transmission of intelli- V gcnce in a multiplex system. Such relays are expensive to build; their maintenance is costly; and the flexibility of adjustment is limited.

Accordingly it is an object of my invention to provide improved facilit'es for the storage. of Signals which may need to be retransmitted from one receiving station to another.

It is another object of my invention to provide a flexible arrangement of terminal equipment in -a telegraph system suchthat incoming signals may either be applied locally to a printer or other responsive device, or, when the occasion arises, these signals may be switched into an outgoing channel of a multiplex or simplex synchronous telegraph system. 1

It is still another object of my invention 'to provide a relaying system which .is characterized by having a minimum number ofmovable parts,

simplicity, and flexibility of adaptation.

It is still another object of my invention to provide receiving and retransmitting equipment in combination with initial code signal transmitting equipment such that incoming and outgoing signals may be handled independently when desired and at other times the incoming signals may be relayed to an outgoing channel.

The foregoing and other objects of my invention will be better understood in view ,of the following detailed description of a preferred embodiment of my invention. This description is ac-' companiedby a drawing. the sole figure of which represents diagrammatically certain apparatus units and their circuit arrangements such as would be found suitableat a given telegraph station.

Referring to the drawing, I show an input circuit having terminals I, and connected thereto is a relay 3, the armature of which is caused by marking signals to close a circuit through its front contact. This relay armature is connected to a continuous ring 15' on a distributor IS. A segmental ring comprises conductive segments 24 interspersed with insulating segments. The rotating brushes 1 connect the segments 24 successively with the ring".

The positiveterminal ofa suitable direct currentsource (not shown) is connected to the front contact of the armature 2! on relay 3. Said source has two sections between which is a grounded tap. The negative section provides a negative grid bias for an amplifier tube l5, as will be hereinafter explained. The brush I is rotated at a synchronous speed such that successive contacts 24 are wiped over by .the brush at the band rate of reception of the code signal elements.

The distributor llv is shown having fourteen conductive segments 24, seven of which are appropriate to code elements of uniform length signals suitable for controlling a printer PA. Seven .others of the conductive segments 2| are arranged to distribute code elements of the signals in another channel to selector means in a printer PB; Either of the printers PA or PB.may be directly connected to the distributor segments by means of multipole double-throw switches 3| and Switch has seven movable contacts II which may be simultaneously engaged with contacts 22 on one side or with contacts 28 on the other sFde.

Printer PA is placed in service by moving the key lever K to the right. The selector mechanism in the printer is conventional and has not, therefore, been shown in detail. A suitable type of selector mechanism includes seven selector magnets and associated code unit latches and code to those for printer PA, but are controlled by the multipole double-throw switch 35 having. lever K.

For purposes of relaying, either of the multipole switches 34 or 3' may be set in the positions shown, thereby to feed all ofthe local impulses representing marking signals through a. single conductor 3| to amovable tap ii ona potentiometer l2, this potentiometer being connected between the grounded neutral point and the negative terminal of the direct current source. The ositive terminal of this source is connected through a resistor II to the front contact of relay 3. Conductor Si is connected to a mid-point on the secondary of transformer ,this secondary having terminals connected respectively with each of the grids in a twin triodetube' IS. The common cathode of this tube is grounded. The anodes are connected to the terminals of a primary winding on atransformer l6. 'l'his'primary winding has a mid-tap which is connected to the positive terminal of the directcurrent source. i

A tone generator has an output-circuit connectedto the primary winding on transformer- II. The output of this generator is, therefore,

arranged to be keyed by the incoming signals. When the armature II is pulled up by relay 3 in response to a marking signal the grid bias in tube It is rendered positive in respect to the grounded cathode. Tube i5, therefore, amplifies the tone frequency output from generator ll.

Upon release of the armature 29 anegative grid a key if desired, consist of a supporting arm which is rotatable about the axis of the drum I, and stationary structure against which the arm can be clamped after suitable adjustment.

A wipe-out magnet ll is disposed in position to de-magnetize the tape 4 immediately preced ing its passage under the pole-piece of the recording magnet il. Magnet II is continuously energized from the direct current source.

tube ll. This tube has the usual cathode, grid,

bias derived from the normal potential drop through potentiometer l2 causes tube It to be blocked. This condition prevails during a spacing signal and thereupon tube l5 delivers no output. The output from the amplifier tube It is coupled across transformer I to a circuit for actuating a recording magnet II on a suitable telegraphone unit. This unit comprises a magformer T. The secondary ll of this transformer is disposed in the input circuit of an amplifier and anode. A cathode resistor is so disposed as to render the tube self-biasing. The end of the resistor 46 remote from the cathode is preferably connected to a neutral ground point.

The anode of tube is connected through the primary winding of a transformer 31 to the posi-- tive terminal of the direct current source. The tone frequency energy derived, from the pick-up magnet 9 is amplified by tube 45 and energizes the primary of transformer II. The secondary of transformer 30 has its terminals connected to the two anodes in a twin diode tube 32. The

netic recording tape l which may be carried on an insulating or non-magnetic drum 5. Alternatively, however, the tape may be carried on two pulleys, one at least of which is motor driven.

The advantage of using a single drum 8 is that no slippage is possible and hence there is no risk of dephasing the recorded signals on the magnetic tape.

Thedrum i may be driven by a synchronous motor i which is supplied with alternating current from a regulated or synchronized source, as is usual. If the drum s is to be driven'at the same speed as that of the brush 1 (and this is a practical arrangement), then the code signals recorded by the magnet II will occupy an arc of 180 for each channel. In the arrangement shown, a complete code signal in channel A is transmitted common cathodeof this tube is connected to one coil terminal of a relay 33. The other coil terminal of this relay is connected to a mid-point on I the secondary of transformer 3.. I

Relay I! has an armature which engages with an electrically positive front contact and a negative back contact. This armature is connected through conductor 39 to contacts 21 in cache! two mutipoledouble-throw switches 30 and 81.

These switches are each appropriate to one of two outgoing channels. of the multiplex system. They are-controlled by key levers M and M'.

The movable contacts I. of the two multipole switches 36 .and II are connected to individual segments on an outgoing signal distributor II.

a This distributor is similar to distributor it except that its conductive segments 38 are separated by and followed by a complete code signal in channel B. It is quite possible, however, to utilize interleaved signals-in which each code element of channel A is followed by one -co'de element of channel B. The latter arrangement is particularl useful when Morse or other .code signals of unequal length are interspersed with uniform length code signals.

A pick-up magnet I is ably positioned with its pointed pole-piece at any radial angle with respect to the pole-piece of the recording magnet i]. In this'manner dinerent intervals of delay may be obtained in the operation of a recording or a relaying device under control of the pick-up magnet I. The means for adiustably positioning the magnet I are not shown. but as is well known, such means may,

TB. Relay II can be switched into circuit 'lfl'l arranged to be adjustrelatively thin insulating segments.

Distributor II has a rotatable brush 'l, which is arranged to contact successively with the ments ll and continuously with the ring IQ. These segments are individually connected through switch contacts '2! and II and'tln'cugh multi-conductor cables 41 to keying contacts (not shown) in the tape transmitters TA and the directcurreut source, the tape transmitters PA and vPB (or either of them) and the tributor 2| and responds to keying under con trol of the conventional perforated tape which is arranged to cntact successively with the seg' rate of passage of brush l over individual segments I8.

Relay ll has an armature It connected to the outgoing line 2. The positive front contact and the negative back contact are arranged to feed current of suitable potential to the outgoing line in accordance with the marking and spacing This delay period 182 elements of the .code signals, the latter being picked up by the brush 3 on distributor 20.

It may .be well now to review the operation of the system when the switches 34 and '36, for example, are set in the position shown for relaying incoming channel A signals to an outgoing chan- .-nel A. Relay 3 biases the tube l5 so as to amplify the output from the tone generator I! upon reception of the marking elements of the code signals. The amplified tone impulse is recorded by magnet I! on magnetic tape 4. The succession of marking elements interspersed with spacing elements is picked up by magnet 3 and the tone frequencies are amplified in tube 45. The marking signal pulses are then rectified in tube 32 and are used to energize relay 33. The armameet any multiplexing requirement simply by orienting the pick-up magnet 3 with respect to the recording magnet I1, I

When it is desired to utilize a local tape transmitter, such 'as the unit TA or the unit TB, in connection with an outgoing multiplex channel,

then the appropriate switch 33 or 31 is set to connect the segments of distributor 23 to individual ones of the code unit contactors in the tape transmitter units, as hereinabove described. Moreover, when the incoming signals are to be locally recorded and not relayed, all of the units PA, PB, TA, and TB may be operated simultaneously, if desired.v Then again, if the-in and .if desired, utilize distributors having a sufllcient number 01' conductive segments 24 and "so that three or more channels may be comprehended in the multiplex system. It is also apparent that in the transmission of code signals each code combination transmitted on one channel may be in succession to a code combination of another and, alternatively. the code elements of diflerently channeled signals may be interleaved simply by connecting alternate segments 24 to one printthe marking. elements of the code ode tube I! does not include the distributor l3, but is directly connected from the tap II on pctentiometer I! to the armature 23 on relay 3.

Furthermore, the functions of relays 33 and ll may be combined in one outputsi'gnal relay it no provision is made for using the local transmitters TA and TB, in which case the distributor would also be eliminated.

Other modifications will readily su est themselves to those skilled in the art and may well be comprehended within the scope of the claims.

I claim: a

1. In a multiplex telegraph system the method of repeating a train of signals received on a selected channel and relayed to a selected outgoing channel, which comprises magnetically record-, ing and reproducing said signals, establishing a predetermined delay period between the instant of recording and the instant of reproduction and so adjusting the value of said delay period that the relayed signals shall be in proper phase relation to signals transmitted over other channels of the multiplex system, thereby to avoid overlapping or the signals in different channels.

2. The method of producing concurrent responses to signal trains of diiIerent channels in a multiplex system, said responses having a phase relation such that the channel times appropriated by each train are mutually exclusive said method'comprising the steps oimagnetically recording incoming signals on a constantly moving medium, picking up said signals by magnetic induction after a predetermined delay period, and

adjusting said delay period to avoid over-lapping of said channel times.

3. In a multiplex telegraph system a station having receiving and outgoing channel terminals, means for magnetically recording signals received on the receiving'yterminals, magnetic pick-up means operable to} repeat said signals, means for so adjusting the pick-up means that a desired delay period is maintained between the or PAand intervening segments to the other the receiving distributor i3 and possibly the sending distributor 23 may be dispensed with in cases where the system asshown and described is to ,be used solely for relaying the incoming signals to a selected outgoing channel or to a plurality 01' different outgoing channels. In such instant of recording and the instant of pick-up of said signals, utilization devices individual to diflerent communication channels of said system, means for allocating said signals to appropriate ones of said utilization devices, and means for delivering a desired portion of said signals to a remotely located utilization device by way of said outgoing channel terminals. 4. In-a system according to claim 3 a code keying device and means for multiplexing the transmission of signals repeated by said pick-up me s with signals produced bysaid keying device, e signals from both sources being sent out by way of said outgoing channel terminals.

5. In a multiplex telegraph system, incoming and outgoing channels wherein a fixed phase displacement is to be maintained between incoming and outgoing signals, a relay responsive to incoming signals. a tone generator subject to keying by said relay, a magnetic tape signal storage device having a recording magnet, r sponsive to, tone frequency energy from said generator as keyed by said relay, a distributor for dividing the outgoing channel time between a plurality of signal'trains, a tape transmitter arranged to deliver one signal train through said distributorto said outgoing channel, and an adinstallations the bias control circuit for the tri- 76 which is delivered by said t pe transmitter;

6. A system according to claim and including a printer responsive to incoming signals and an incoming signal distributor arranged to so segregate .the signals of difierent trains that one train is applied for control of said printer while another train is applied to the first said relay for keying the output from said tgne generator.

7. Apparatus for translating code unit signals, comprising a composite signal channel, a magnetic tape storage device having recording, reproducing and wipe-out magnets in juxtaposition to an endless recording tape, the recording magnet being energized by signals received on said channel, and the wipe-out magnet-being continuously energized, means for orienting the reproducing magnet with respect to the recording magnet thereby to obtain a predetermined delayperiod for the reproduction of signals, a

second composite signal channel arranged to be assumes a suitable time" lapse between the instant of re-' cording. a given signal and the instant of'reproducing the same by said pick-up means, switching means settable at willto allocate incoming signals of a desired channel to one of said printer lmits 'or to said storage device, and other switching means settable at will to draw upon said pick-up means or upon one or said keying units for signals to be applied to a desired outgoing channel.

11. In combination, a m l storage device in eluding magnetic tape recording and pick-up meangasoumeofincomingcodesignalsapplicable to said storage device, a code signal keyer constituting a second signal source, means providing transmission of the signaisfrom the twosaid sources at a uniform baud rate, distributor means for multiplexing the signals from the two said sources, and means for soadiusting the delay period introduced by feeding the incoming signals fed with signals from diilerent sources, and

means for utilizing said storage said sources.

- 8. In amultiplex telegraph system, a relaying device comprising receiving terminals and transmitting als, means including a-magnetic tape -re rdin'g unit and-a printer unit, both responsive to signal potentials of multiplexed signalingchannels impressed on said receiving terminals, means for scanning the recordmade device as one of by said unit, means for segregating portions of the scanned record which are appropriate to a given one 'of the multiplex channels, means for tone modulating the signal potentials to which said tape recording unit is responsive, an'independent source of outgoing signals, and phasing means for maintaining a suitable channel time 'separation of said signals from the output of said scanning means.

9. A phasing device for a synchronous telegraph system comprising magnetic tape signal recording'and signal reproducing means, a receiving circuit for applying incoming signals to said recording means, a printer having character selecting means responsive to signals applied thereto from said receiving circuit, switching means for effecting concurrent operation of said recording means and of said printer when desired, and for eilecting independent and sole operation of said recording means or said printer when desired, a code keying device operable at thesame code element speed as that of the incoming signals, an outgoing signal channel, means for relaying a desired portion of the recorded and reproduced signals to said outgoing channel, means for multiplexing said reproduced signals with simals deadiusting the phase relation between the signals derived from said reproducing means and the signals derived from said keying device that said signals are caused to occupy mutually exclusive portions of the outgoing channel time.

10. In a multiplex telegraph system having incoming and outgoing channels and synchronizing means for maataining time division of said channels with respect to'diflerent trains of signals, a

, plurality of printer units arranged for control by incoming code signals, a plurality of code signal keying units arranged tqdeliver signal potentials to selected ones of said outgoing channels;a signal storage device including magnetic tape recording and pick-up means, a phase adjuster for obtaining through said storage device that'a suitable phase relation is maintained between the signals from the two said sources. v a

d 12. In a multiplex telegraph system for locally locally sending, and relaying cork sigrials the elements of which are of uniform length, an incoming signal distributor, an outgoing distributor, a pluralityof printers, a plurality of code keyers, selective circuits extending through said incoming distributor to saidfprinters. coilating circuits extending from said keyers to said outgoing distributor, a tone modulator subject to control at mutually exclusive times by the code elements of diiferent trains of incoming signals,

rived from said keying device, and means for so switching means for determining the manner of utilization of the incoming code signals by saidprinters, said tone modulator, or either of them, other switching means for determining the sources of different trains of signals to be applied to said Outgoing distributor, and incoming signal store-s means having a continuously movable tape of magnetizable material in cooperative relation to a magnetic recording element, a magnetic reproducing element and a wipe-out magnet, said storage means being arranged to suitably delay trains, electromagnetically recording. and reproducing said keyed wave, introducing a predetermined storage period between said recording and reproduced steps with respect to a given element in said train, amplifying and rectifying said wave, and relaying the code elements derived from said rectified wave and from the other said train-to said outgoing multiplex channel.

14. The method according to claim 13 and including the step of locally translating the'intelligence of one train of incoming signals in an incoming multiplex channel while simultaneously utilizing another train derived from said incoming multiplex channel to key said tone frequency wave.

JOHN L CALLAHAN. 

